The effect of immunosuppression on the patency and structure of canine vein allografts in the venous system.

The effect of immunosuppression on allogeneic femoral vein grafts placed into the venous system of dogs was studied. Autologous vein grafts demonstrated clear patency and few histologic changes up to four weeks after operation. Allogeneic vein grafts in dogs not receiving immunosuppression showed thrombosis in all instances within less than four weeks. Standard immunosuppression therapy reduced the thrombosis rate to 25 per cent at four weeks in dogs with femoral vein allografts. Only mild histologic changes were observed in these grafts.